Saturday, 18 May 2024

Third mosquito sample tests positive for West Nile Virus

LAKE COUNTY – Lake County officials reported Thursday that another mosquito sample found locally has tested positive for West Nile Virus, and they're asking county residents to be especially vigilant in taking precautions to deal with mosquitoes over the holiday weekend.

The Lake County Vector Control District and Lake County Health Services reported that they received confirmation that the third mosquito sample collected in Lake County, this time near Upper Lake on Aug. 18, showed the presence of West Nile Virus.

The two previous positive mosquito samples were from Lakeport, as Lake County News reported earlier this month.

So far this year, 1,101 West Nile-infected mosquito samples have been reported statewide, with nearly 300 of those found in Los Angeles County, according to the state's West Nile Virus Web site.

There have been 103 human cases in 13 counties – more than half in Los Angeles and Orange counties combined, the state reported. No human cases have been reported in Lake County.

In addition, 1,456 dead birds, 109 sentinel chickens, 10 squirrels and five horses have been infected with the disease across California. Lake County has had no reports of any of those animals being infected.

West Nile virus is transmitted by mosquitoes to a variety of animals and to humans. Mosquito and vector control agencies usually detect the virus in mosquitoes, birds and sometimes tree squirrels before human cases appear, according to the Thursday report.

The best way to stay healthy during West Nile virus season is to prevent exposure to mosquito bites, local officials said Thursday. West Nile virus is present throughout most of California, so if you plan to be outside, use a mosquito repellent.

Lake County Health Officer Dr. Karen Tait said that, when properly used, mosquito repellents that have been registered with the U.S. Environmental Protection Agency are safe and effective. She added that people should not rely on products that have not been scientifically tested.

Dr. Jamesina Scott, district manager and research director for the Lake County Vector Control District, said the agency is working hard to reduce the risk of mosquito bites and West Nile virus to Lake County residents and visitors.

However, there's one area they need help – and that's with finding backyard water sources like neglected swimming pools or ornamental ponds that can be mosquito breeding grounds, Scott said.

“Mosquitoes are easy to control in these habitats if we know where they are. Just one neglected swimming pool can produce thousands of mosquitoes per day, and cause problems for an entire neighborhood,” she explained.

The message local health officials emphasize to residents is the need to drain standing water sources around homes that may breed mosquitoes. People also need to protect themselves with long sleeves or an effective repellent during dawn and dusk when mosquitoes are most active.

Most people who become infected with West Nile virus do not show symptoms and will recover uneventfully, officials reported. Up to 20 percent of people will develop fever, headache and other nonspecific symptoms that may last several weeks. Approximately one in 150 people will develop severe illness known as neuroinvasive disease. People over age 50 and diabetics appear to be at most risk for the more severe forms of disease.

While there is no human West Nile Virus vaccine, very good equine vaccines are available and officials strongly recommended having horses vaccinated because the disease is potentially fatal for the animals. When West Nile Virus first hit the state several years ago, hundreds of horses died or were euthanized in the disease's initial peak years in California.

Residents can request service, get mosquitofish, or report neglected swimming pools to Lake County Vector Control District at 263-4770 or This email address is being protected from spambots. You need JavaScript enabled to view it..

To report a dead bird or squirrel, call 1-877-WNV-BIRD (1-877-968-2473) or visit the California Department of Public Health’s West Nile virus website at

For additional information on West Nile virus, visit, or


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05.18.2024 10:00 am - 1:00 pm
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